1. Field of the Invention
The present invention relates to a method and apparatus for inspecting wire breaking of an integrated circuit. Specifically, the present invention relates to a method and apparatus for inspecting wire breaking of an integrated circuit via space in a non-contact manner by using combination of photo excitation and the radiated electromagnetic wave detection.
2. Description of the Related Art
As an inspection apparatus for wire breaking of a semiconductor integrated circuit, an observation apparatus such as a X-ray inspection apparatus and a microscope has conventionally been known. However, both of the X-ray inspection apparatus and the microscope use a technique of visually specifying a wire breaking portion by imaging, and in this technique, it is difficult to detect a wire breaking of a minute crack at a portion such as a solder connection portion where imaging is difficult. Further, there is a fear that using of the X-ray inspection apparatus for a long time may harm the health of the operator.
On the other hand, in the most commonly used inspection method, inspection of wire breaking is performed in a voltage applied state by using a tester that directly measures a voltage. However, there are the following problems. In reality, this method cannot be applied to the inspection of wire breaking of an integrated circuit because the wire of the integrated circuit is too minute. Further, in this method, wiring for voltage detection is required because when the tester does not contact with a target wire, the inspection cannot be performed.
Besides the above-mentioned known inspection apparatuses and methods, an electron beam tester that detects a voltage of an electric wire is known as a conventional technique that is used for wire breaking inspection of an integrated circuit. For example, this technique is disclosed in the following Documents 1 and 2.
[Document 1]
K. Nikawa, “Failure Analysis in Si Device Chips”, IEICE Trans. Electron., Vol. E77-C, No. 4, pp. 528–534.
[Document 2]
TODOKORO H, FUKUHARA S, KONODA T, “ELECTRON-BEAM LSI TESTER”, JAPAN ANNUAL REVIEWS IN ELECTRONICS COMPUTERS & TELECOMMUNICATIONS, vol. 13, pp. 373–382 (1984).
In addition, wire breaking malfunction detection apparatuses for a semiconductor integrated circuit (disclosed in the following Documents 3 and 4) have already been applied for a patent.
[Document 3]
Japanese Laid-Open Patent Publication No. 2000-311929.
[Document 4]
Japanese Laid-Open Patent Publication No. 2000-36525.
According to “Wire Breaking Malfunction Detection Apparatus and Wire Breaking Malfunction Detection Method for Semiconductor Integrated Circuit” disclosed in Document 3, in an integrated circuit manufacturing process, an electron beam injection is performed on a wafer that has undergone one process, from the side at which a wiring layer is formed. Alternatively, electrical charge is used that is generated by mutual interaction between plasma and a wafer surface in the manufacturing process and that is generated on the side at which electrical wires are formed. In these manners, an electric field is generated in a diffusion layer. Then, a laser beam injection is performed from the back side of the substrate so that photoelectric effect detection device can detect a phase and intensity change of the reflection light of the laser beam caused by a change of the generated electrical field. By the detected phase and intensity change of the reflection light, it is possible to specify the wire having wire breaking malfunction.
According to “Wire Breaking Malfunction Detection Apparatus and Method for Semiconductor Integrated Circuit, and Storage Medium” disclosed in Document 4, a power source line voltage having a shape of a pulse is applied to a power source line of an inspection target LSI, a grounded line voltage that has a shape of a pulse and of which phase is shifted by 180 degrees from the phase of the power source line voltage is applied to a grounded line, and a signal line voltage that is constant is applied to a signal line. This LSI is irradiated with an electron beam, and amounts of secondary electrons emitted from the LSI during a period T1 immediately after the power source line voltage rises and during a period T2 immediately after the power source line voltage falls are detected. Based on these detection results, a voltage image in a malfunction state (of which brightness becomes different at the forward and backward sides of the wire breaking position when the wire breaking exists), and a voltage image in a normal state (of which brightness does not become different at the forward and backward sides of the wire breaking position even when the wire breaking exists) are formed. Then, the voltage image in the malfunction state and the voltage image in the normal state are alternately displayed on a displaying device.
Furthermore, another technique related to the present invention is disclosed in Document 5.
[Document 5]
D. H. Auston and M. C. Nuss, “ELECTROOPTIC GENERATION AND DETECTION OF FEMTOSECOND ELECTRICAL TRANSIENTS”, IEEE JOURNAL OF QUANTUM ELECTRONICS, volume 24, pp. 184–197 (FEB. 1988), Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, NEW YORK, IDS No.: M6712, ISSN: 0018-9197.
In the case of the above-mentioned electron beam testers of Documents 1 and 2, and the wire breaking malfunction detection apparatus of Documents 3 and 4, an electron beam generation source is needed, and the electron beam irradiation needs to be performed on an integrated circuit set in a vacuum chamber. Accordingly, there is a problem in that the apparatus becomes expensive, and the size of the apparatus becomes large.